Numerical simulation method of dnapl migration based on 3D microstructural model of porous media

Abstract

The invention provides a porous medium three-dimensional microstructure model-based DNAPL migration numerical simulation method. By building a three-dimensional microstructure model of a right squarepyramid is built, the porosity of a semi-transparent porous medium is accurately measured through visible light by utilizing a visible light micro-imaging technology, and the permeability and the capillary inlet pressure are calculated out by using the porous medium three-dimensional microstructure model. Based on accurate measurement of the permeability and the capillary inlet pressure of the semi-transparent porous medium, the scale of a representative elementary volume is quantitatively assessed by using a relative gradient error. A dense non-aqueous phase liquid migration model is built byusing UTCHEM, and the two-dimensional semi-transparent porous medium is divided by taking the REV as a grid scale, so that the simulation precision of DNAPL migration is improved and the quantitativedetermination of a model division grid is realized. According to the method, more accurate quantitative determination of the properties and the grid scale of the porous medium is realized; and the method has relatively high applicability in accurate simulation of migration and even restoration process in an aquifer and establishment of corresponding pollutant restoration schemes.

Description

technical field [0001] The invention relates to a heavy non-aqueous phase pollutant, in particular to a DNAPL migration numerical simulation method. Background technique [0002] With the rapid development of industry and agriculture, human activities release more and more dense nonaqueous phase liquid DNAPL into nature. The leaked DNAPL has low solubility and higher density than water. After entering the aquifer, the DNAPL will always infiltrate and migrate to the deep part of the aquifer, and it is easy to stay on the low-permeability medium to form a polluted pool and remain. Because DNAPL such as perchloroethylene (PCE) and polycyclic aromatic hydrocarbons (polycyclic aromatic hydrocarbons, PAHs) have stable chemical properties, low solubility, high toxicity, and carcinogenicity, the residual DNAPL in the aquifer will cause serious damage to the groundwater environment. Long-term pollution will cause serious harm to human health in the ecosystem. When DNAPL enters the ...

AI Technical Summary

Problems solved by technology

However, the research of these fractal methods on porous media is limited to the theoretical point of view, and the microstructure models of porous media constructed are mostly ideal two-dimensional models, but the actual microstructure of porous media is three-dimensional, so the properties of porous media in actual measurement are different. Difficult to obtain accurately with current fractal methods

In addition, the numerical model of DNAPL migration usually determines the grid scale of the aquifer in a qualitative way, with a lot of randomness

Therefore, the current visible light imaging technology and fractal methods cannot quantitatively and accurately measure the key parameters (permeability, capillary entry pressure) and corresponding REV of translucent porous media such as translucent quartz sand in practice.

This will make it difficult to quantitatively determine the properties of porous media and the meshing scale of the numerical model of DNAPL migration in porous media, resulting in errors in simulations

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